Delayed intensification phase, day one was Friday?

My son is 17 and a half months old and cannot tell me what he is feeling. He has High Risk Acute Lymphoblastic Leukemia and he began his delayed intensification phase yesterday. He had IV push Doxorubicin 25 mg, IV push Vincristine 1.5 mg, and he is now on a twice daily steroid called Decadron. The doctor told me that for the first day he would be pukey and for the following weeks he would be cranky, angry, and needy. True to her word, he threw up all day yesterday and woke up today screaming. I haven't called the Dr. because I don't know if it's the steroid but he's screaming and screaming and nothing is right. He aks for something, I give it to him and he screams. I don't know what to do, how normal is this? It's rather upsetting.